Rotary extruder

Abstract

The present rotary extruder includes: a rotor having a cylindrical surface centered on a rotor axis extending in a horizontal direction; and a casing having an inner peripheral surface that defines a bore, wherein: the casing defines an input port into which a resin material including a thermoplastic resin is fed, and a discharge port from which a plasticized molten resin is discharged; the cylindrical surface of the rotor and the inner peripheral surface of the casing are arranged eccentric with each other, thereby forming a gap whose cross section is crescent-shaped, extending in a rotation direction of the rotor from the input port to the discharge port between the inner peripheral surface and the cylindrical surface; and the input port is arranged at a top portion of the casing and the discharge port is arranged at a lower portion of the casing.

1 . A rotary extruder comprising:
 a rotor having a cylindrical surface centered on a rotor axis extending in a horizontal direction; and   a casing having an inner peripheral surface that defines a cylindrical hole extending in the horizontal direction, wherein:   the casing defines an input port into which a resin material including a thermoplastic resin is fed, and a discharge port from which a molten resin, obtained by kneading and plasticizing the resin material, is discharged;   the cylindrical surface of the rotor and the inner peripheral surface of the casing are arranged eccentric with each other, thereby forming a kneading section, which is a gap whose cross section is crescent-shaped, extending in a rotation direction of the rotor from the input port to the discharge port between the inner peripheral surface of the casing and the cylindrical surface of the rotor; and   the input port is arranged at a top portion of the casing and the discharge port is arranged at a lower portion on an opposite side from the top portion of the casing.   
     
     
         2 . The rotary extruder according to  claim 1 , wherein the kneading section extends halfway around the rotor from the input port to a lowest portion of the rotor, and further extends from the lowest portion of the rotor to the discharge port, which is above the lowest portion and below a position that is orthogonally sideward of the rotor. 
     
     
         3 . The rotary extruder according to  claim 2 , wherein a non-kneading section is formed between the casing and the rotor, the non-kneading section extending from a position that is downstream of the discharge port in the rotation direction of the rotor to a position that is upstream of the input port in the rotation direction, wherein the rotor closely opposes the inner peripheral surface of the casing. 
     
     
         4 . The rotary extruder according to  claim 3 , wherein:
 in the non-kneading section, the cylindrical surface of the rotor closely opposes the inner peripheral surface of the casing; and   in the kneading section, the inner peripheral surface of the casing distantly opposes the cylindrical surface of the rotor.   
     
     
         5 . The rotary extruder according to  claim 4 , wherein:
 the casing is provided with a first weir and a second weir, which are boundaries between the kneading section and the non-kneading section;   the kneading section extends from the first weir in the rotation direction of the rotor to the second weir; and   the non-kneading section extends from the second weir in the rotation direction of the rotor to the first weir.   
     
     
         6 . The rotary extruder according to  claim 5 , wherein:
 the inner peripheral surface of the casing has a first surface and a second surface that are continuous with each other in a circumferential direction;   the first surface defines the kneading section and the second surface defines the non-kneading section; and   a radius of curvature of the first surface is larger than a radius of curvature of the rotor, and a radius of curvature of the second surface is smaller than the radius of curvature of the first surface.   
     
     
         7 . The rotary extruder according to  claim 6 , wherein the first weir and the second weir are arranged at boundaries between the first surface and the second surface, extend in a radial direction of the rotor, and are each formed in a stepped shape. 
     
     
         8 . The rotary extruder according to  claim 2 , wherein the crescent-shaped gap narrows from the top portion toward a side portion upstream of the lowest portion. 
     
     
         9 . The rotary extruder according to  claim 8 , wherein the crescent-shaped gap further narrows from the side portion toward the lowest portion.